The present invention relates to a process for in-situ treatment of wood poles and especially to the treatment of wooden utility poles against deterioration.
Wood poles make up a substantial percentage of poles used in transmission and distribution of electricity throughout the world. Since wood is a natural material, it is susceptible to deterioration by decay organisms especially at the ground line where the wood pole is supported in the earth. To extend the life of wooden utility poles, the poles are pressure treated before installation with volatile chemicals, such as creosote, pentachlorophenol, and various combinations of arsenic salts and the like. Even though wooden poles are treated under pressure, the depth of penetration of the chemicals is typically limited to the outside two or three inches of the pole. The wooden poles were once living trees and contain living decay organisms or fungi that remain in the interior untreated section of the pole even after treatment. When the wood pole is placed in the ground, natural weathering allows these decay organisms to flourish resulting in the formation of voids in the wood and thus a loss of structural integrity of the pole. This is especially true within the poles adjacent the ground lines where the poles enter the earth since the poles in the earth tend to absorb and accumulate moisture in the base which encourages the growth of fungi and other decay organisms. Typical methods used to arrest this decay include the application of highly toxic chemicals and fumigants that are injected into the void area created by the decay organisms. In addition, biocides are painted on the outside of the pole below the ground line to prevent additional undesirable organisms from entering the wood from the soil.
The present invention is a method for arresting wood pole decay and pole ground line decay in an existing utility pole which has previously been treated. This is accomplished by sealing the wood and reactivating the existing preservative by using an injection treatment of an isophorone solvent into poles drilled into the base of the pole and by coating the base of the pole with an isophorone formulated paint. The painted area of the pole may also be covered with a moisture impenetrable polymer film for sealing the outside of a base pole from the ground line. Since isophorone migrates through moisture, it is necessary to provide a moisture barrier to keep it from escaping into the moist soil.
One prior patent to Tomlinson, Sr. et al., U.S. Pat. No. 4,414,227, teaches a method for repelling birds, especially woodpeckers, from selected areas or surfaces which comprises applying isophorone in such areas or surfaces. Isophorone is an organic solvent that has been found effective in repelling the woodpeckers and has a molecular structure that is highly miscible in water.
The present invention deals with an isophorone formulated chemical coating and sealant for coating the ground line area of an existing pressure treated utility pole and to a process which drills holes in the utility pole for injecting an isophorone compound thereinto in those poles previously pressure treated with an oil-based preservative, such as creosote or pentachlorophenol. Tests have shown that the composition when applied in accordance with the present process has been found effective in arresting further decay within the poles.